ONTOGENIC DIET SHIFTS IN AGE-0 STRIPED-BASS, MORONE-SAXATILIS, FROM THE MIRAMICHI RIVER ESTUARY, GULF-OF-ST-LAWRENCE

Stomach contents of 2928 age-0 striped bass, Morone saxatilis (3.9-153 .3 mm total length (TL)), collected from June to November 1992 in the Miramichi River estuary were examined. Seventy-seven percent of the fi sh stomachs examined contained food organisms and 34 prey taxa were id entified. Larval striped bass (<25 mm TL) fed primarily on immature an d adult copepods. The onset of exogenous feeding correlated both spati ally and temporally with a peak in the abundance of prey. Chesson's al pha index indicated progressive selection of larger prey with increasi ng size of larval striped bass, from small rotifers to larger calanoid copepods to the relatively large calanoid Eurytemora sp. Mysids (Neom ysis americana) and sand shrimp (Crangon septemspinosa) were the princ ipal prey of striped bass >50 mm TL. Contributions by other prey group s (molluscs, polychaetes, amphipods, insects, and larval fish) were mi nor. Large underyearlings, 64-84 mm TL, in near-fresh water ate propor tionally more mysids than fish downriver in more saline waters. Feedin g ceased when water temperatures declined below about 3 degrees C in N ovember.